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TRANSFERRING AN ESTABLISHED LIVE SAND
FILTER
For those of you utilizing an NNR (natural nitrate
reduction) live sand filter in your current reef set-up, you may be faced with the
prospect of upgrading to a larger tank at some point during the life of your reef,
requiring the transfer and expansion of an established sand bed.
Several months ago, I upgraded our 125-gallon display to
a 180-gallon, and was interested in the possibility/feasibility of transferring the
existing sand bed to the new 180. Having never moved an existing live sand filter to
a larger aquarium (which requires adding additional dry aragonite due to the increased
volume of the new tank), I contacted Bob Goemans, renowned hobbyist and columnist, and an
expert in natural filtration techniques.
My question and Bob's answer are reprinted below:
Q:
I have a 125-gallon reef which has been set up with a live sand filter per your
specifications for four years. I am in the process of upgrading to a 180-gallon tank
and would like to transfer the sand from the 125 to the 180. Do you think it would
be better to add the additional sand I will be needing for the larger system to the top of
the sand bed or the bottom? I have installed live sand filters per your
specifications in all of my tanks (12 of various sizes), as well as all of my customers'
tanks and have been very happy with the results. Thanks for all of your great
information in your articles.
A:
Thanks for your question and the plenum feedback. As for your question, once
the sand is removed from the 125, the microbes living on their individual sand grains in
the separate oxic and anoxic zones will be all mixed together. If your goal were to
add another inch of substrate using a dry material, I would simply place that new inch on
top of the grid, then add the sand from the old aquarium. The oxygen gradient will
quickly establish itself, and those microbes in their proper zone will continue to
function. This way, basic processes are not overly disturbed as would be if the
upper inch was all new and the nitrification and mineralization microbes had to completely
re-establish themselves.
USE OF A LIVE SAND FILTER
IN YOUR REEF AQUARIUM
One of the main components of the natural
reef aquarium is the NNR (natural nitrate reduction) live sand filter. Many hobbyists
wonder whether conversion to this method of natural filtration is worth the time and
effort. Our firm belief is yes — the benefits of an NNR filter far outweigh the
commitment of re-doing your reef and waiting for the denitrification process to become
fully mature and functional.
This simple filter, which consists of a
thick layer of aragonite reef sand raised slightly above the bottom by a sheet of
egg-crate and fiberglass screen, was developed by Dr. Jean Jaubert and has only recently
become widely accepted as the most effective method of eliminating nitrates and
maintaining a balanced reef system.
After the sand is seeded by your live rock,
a plenum of anoxic water develops under the egg-crate, creating a perfect place for
denitrifying bacteria to thrive in the low-to-zero oxygen conditions on the bottom. The
small organisms in the sand keep the substrate healthy, and the dissolution of calcareous
sand returns ions such as calcium and carbonate to the water. Not only will you notice
higher levels of calcium and alkalinity, along with exceptionally fast coral growth rates,
but your overall maintenance regimen will decrease, with less frequent large water changes
and calcium or buffer additions. |
LIGHT
BULB MAINTENANCE ON YOUR REEF AQUARIUM
Changing your light bulbs and/or tubes at regular
intervals will go a long way toward keeping your reef healthy and growing. Some corals
(especially certain species of SPS corals) and clams can suffer or die in aquariums where
the lights have not been replaced regularly.
We recommend changing fluorescent lighting (RO,
HO & VHO) at 6-month intervals. Over time, fluorescent tubes can lose as much as 35%
of their illumination, and the color spectrum will shift considerably in certain tubes.
You can potentially get significantly more life and illumination out of your bulbs with
the use of an electronic ballast.
Metal halide bulbs vary in their useful life
span, depending on tank size and the types of corals being kept. For example, the 10K
German bulbs may require replacement every 7 months in a tank containing certain species
of SPS corals, whereas an Iwasaki 6500K bulb will be effective for 12 or more months under
the same conditions. Close monitoring of your corals is a definite indicator. Signs of
bulb inefficiencies manifested in your corals include change of color, bleaching or slow
to no growth.
If you are unsure whether a bulb is past its
prime, keep a spare set and change out one bulb after a certain period and compare
the intensity and spectrum of the new bulb or tube against the remaining older bulb in
your fixture. Because a new bulb burns much brighter during its initial "burn-in
period," run the new bulb for two weeks before making your comparison.
Please feel free to e-mail
us with any questions or concerns you may have regarding lighting for the reef aquarium.
MAINTAINING AN NNR LIVE SAND FILTER
After an NNR (natural nitrate
reduction) sand filter is activated (about 6-8 weeks), it requires only minimal attention
– in fact, the less you do to it, the better it performs. In the first few weeks, you
may notice a thin brown layer of algae forming on the sand. Lightly fanning the sand
surface will keep it under control, although it will dissipate naturally after the
bacterial populations begin to multiply. At 8 weeks, the nitrates will drop to zero, and
the filter will be in full swing.
One of the biggest mistakes hobbyists make
with a live sand filter is employing "traditional" maintenance methods –
vigorous vacuuming and overdosing of additives and buffers. Vacuuming will aerate the sand
bed, killing the denitrifying bacteria and eliminating the worms and crustaceans
populating the sand. Problem areas can be lightly vacuumed, but no more than ½"
deep. In the first two months alkalinity and calcium levels will fluctuate, but should not
be adjusted. After this period, addition of buffers and calcium should be done sparingly
(if at all), and spread out over time. Levels of alkalinity and calcium should be kept as
close to natural seawater as possible: alkalinity 2.1-2.5meq/l; calcium 380 ppm –
high levels can actually cause sand clumping and a crash of alkalinity and calcium. The
primary components of aragonite - calcium, carbonate and strontium - will be slowly added
to your water as the sand dissolves. As a result, more sand should be added to maintain
the depth of your sand bed.
Lastly, one of the most effective ways of
keeping your system as close to natural seawater as possible is through regular partial
water changes with good quality salt.
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